The present invention relates to a method of supplying a fine-particle powder from a container to another vessel or a hopper provided in an electrostatic printing apparatus or the like, and more particularly to a method in which by causing part of said container to engage with part of the apparatus, said container is maintained stationary such that a powder can spontaneously be supplied to said apparatus. For convenience in explanation, the following description will be given with reference to an electrophotographic copying apparatus.
In such an apparatus, it is well known that an electrostatic latent image formed on a photoreceptor is visualized in a development process. It is also well known that an amount of toner is suitably re-supplied to stabilize, in amount, the toner in the developer which may otherwise decrease as the development process is repeated. The description will be given in connection with a so-called two-component developer including ferromagnetic particles which are called "carrier", such as iron particles, and toner particles. It is to be understood, however, that the present invention can be applied to other similar apparatuses utilizing a magnetic one-component toner (one-component developer) in which the ferromagnetic particles unite with resinous particles (toner), and other powders. The objective powder used in apparatuses to which the present invention can be applied will now be referred to as "toner" representatively.
There have been proposed the following methods of supplying the toner:
(1) After a developing device has been removed from the body of an apparatus, the opening of a hopper mounted on the apparatus is engaged by the mouth of a toner container which will be in turn tilted to supply the toner therein to the hopper.
(2) A toner containing cartridge is slid to a hopper along rails in the body of the apparatus. After the cartridge has been positioned relative to the hopper, part of the cartridge is broken through any suitable means such as string or the like to supply the toner therein to the hopper.
(3) After removing a closure, an opened toner container is fixedly mounted on the toner receiving portion of a developing device by means of a threaded portion formed on the body of the container.
In such a position, the closure can be re-mounted on the container. The container is left intact in this position until the previously supplied toner in the developing device will have been consumed.
The first prior art method has a disadvantage in that the toner is scattered or floats in the air on supplying it because of very small specific gravity of the toner which is in the form of fine particles having particle diameters in the range of about 5.about.30 .mu.m, resulting in contamination of the surrounding areas and the hands and garment of an operator.
The second prior art method is an improvement to the first method, but has also a disadvantage in that the operation is very cumbersome because the cartridge must manually be manipulated after it has been set in position.
The third prior art method is most convenient of the three prior art methods mentioned above. However, the toner container must always be mounted within the apparatus even if the re-supply of toner is not required. This means that an excess space is required, resulting in a large-sized machine.